JP5740233B2 - Electronic component mounting equipment - Google Patents

Description

  The present invention relates to an electronic component mounting apparatus that mounts a component supplied from an electronic component supply device on a substrate, and in particular, returns to the origin of a belt that connects a shaft of a nozzle that sucks the component and a shaft of a motor that rotates the nozzle. The present invention relates to an electronic component mounting apparatus.

Conventionally, in an electronic component mounting apparatus, an electronic component is sucked and held by a suction nozzle that can operate in the X, Y, Z, and θ-axis directions, and the electronic component is mounted on a substrate.
In such an electronic component mounting apparatus, for example, there is a technique described in Patent Document 1 as an improvement in mounting accuracy by improving the rotational position accuracy around the axis of the suction nozzle. In this electronic component mounting apparatus, the shaft of the suction nozzle and the shaft of the θ-axis motor that rotates the suction nozzle are connected by a belt, and the driving force of the θ-axis motor is transmitted to the suction nozzle. The belt origin is searched by detecting this with a sensor, and the belt origin return is performed.

JP 2009-124083 A

However, in the conventional apparatus described in Patent Document 1, the belt mark may be difficult to detect due to deterioration over time, rubbing of the belt, and the like, and there is a concern about durability.
SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic component mounting apparatus that can stably perform return-to-origin of a belt that connects a suction nozzle shaft and a motor shaft that rotates the suction nozzle.

  In order to solve the above-described problem, an electronic component mounting apparatus according to claim 1 sucks an electronic component by a suction nozzle mounted on a nozzle shaft rotated by a θ-axis motor, and mounts the electronic component on a substrate. An electronic component mounting apparatus comprising: a toothed drive pulley mounted coaxially with the shaft on the axis of the θ-axis motor; and a toothed first mounted coaxially with the nozzle shaft on the nozzle shaft. A driven pulley, a second driven pulley with at least one tooth, the drive pulley, the first driven pulley, and the second driven pulley, and the number of teeth of the drive pulley and the first A toothed belt having the same number of teeth as the least common multiple of the number of teeth of the driven pulley, and a first origin detection signal that outputs a first origin detection signal when the drive pulley is at the origin. And a second origin detection means for outputting a second origin detection signal when the second driven pulley is at the origin, and the first origin detection signal output by the first origin detection means. And an origin return means for returning the belt to the origin based on the second origin detection signal output from the second origin detection means.

  In this way, the number of teeth of the belt that transmits the driving force of the θ-axis motor to the nozzle shaft is made to coincide with the least common multiple of the number of teeth of the driving pulley and the number of teeth of the second driven pulley, so the belt makes one round. Only once in between can the timing at which the drive pulley and the second driven pulley both become the origin can be made. Further, the amount of deviation from the origin of the second driven pulley when the drive pulley is at the origin and the amount of deviation from the origin of the drive pulley when the second driven pulley is at the origin can be made regular. it can.

  Therefore, based on the output timing of the first origin detection signal and the output timing of the second origin detection signal, the belt origin can be appropriately searched and the origin return can be performed. At that time, since it is not necessary to attach a belt mark to the belt as in the conventional apparatus, even if aged deterioration, belt rubbing or the like occurs, the belt origin return operation is not affected. Therefore, the belt origin return can be performed stably.

According to a second aspect of the present invention, in the electronic component mounting apparatus according to the first aspect, when the belt is at the origin, the drive pulley and the second driven pulley are both assembled at the origin. It is characterized by that.
Thereby, only when the belt is at the origin, the output timing of the first origin detection signal can coincide with the output timing of the second origin detection signal. Therefore, the belt origin can be easily searched.

  The electronic component mounting apparatus according to a third aspect is the invention according to the second aspect, wherein the origin return means rotates the θ-axis motor while the first origin detection means and the second origin detection. Search means for searching for the timing at which the means simultaneously outputs the origin detection signal, and motor stop means for stopping the rotation of the θ-axis motor at the timing searched by the search means.

  Thus, only when the belt is at the origin, the first origin detection signal output timing and the second origin detection signal output timing coincide with each other, and the first axis detection motor rotates while rotating the θ-axis motor. When the first origin detection signal is output, it is confirmed whether the second origin detection signal is also output. When the first origin detection signal is output, the second origin detection signal is also output. When this is confirmed, the rotation of the θ-axis motor is stopped. Thereby, the θ-axis motor can be stopped when the belt returns to the origin. That is, the belt origin search and the origin return can be performed simultaneously.

  According to a fourth aspect of the present invention, in the electronic component mounting apparatus according to the first or second aspect of the present invention, the electronic component mounting apparatus further includes a pulley angle detection unit that detects a rotation angle of the second driven pulley, and the origin return unit includes the first return unit. Based on the rotation angle of the second driven pulley detected by the angle detection means when the first origin detection means outputs the first origin detection signal, the deviation amount from the origin of the belt at that time is calculated. Based on the deviation amount calculation means to be calculated, and the deviation amount from the origin of the belt calculated by the deviation amount calculation means, the rotation direction and the rotation amount of the θ-axis motor necessary for returning the belt to the origin are calculated. Motor control amount calculation means for calculating; motor drive means for rotating the θ-axis motor in the rotation direction calculated by the motor control amount calculation means by the rotation amount calculated by the motor control amount calculation means; It is characterized by providing.

  Since the rotation angle of the second driven pulley when the driving pulley is at the origin is regular, if the rotation angle of the second driven pulley at the time when the first origin detection signal is output can be detected, Based on the detected angle, it is possible to appropriately recognize the current belt position (deviation amount from the origin). Then, after recognizing the current belt position, the θ-axis motor can be rotated at once to return the belt to the origin. In this manner, the belt origin return operation can be performed appropriately and quickly.

  Furthermore, an electronic component mounting apparatus according to a fifth aspect is the invention according to the first or second aspect, further comprising motor angle detection means for detecting a rotation angle of the θ-axis motor, wherein the origin return means is the second return means. Based on the rotation angle of the θ-axis motor detected by the motor angle detection means when the origin detection means outputs a second origin detection signal, a deviation amount from the origin of the belt at that time is calculated. Based on the deviation amount calculation means and the deviation amount from the origin of the belt calculated by the deviation amount calculation means, the rotation direction and the rotation amount of the θ-axis motor necessary for returning the belt to the origin are calculated. Motor control amount calculation means; and motor drive means for rotating the θ-axis motor in the rotation direction calculated by the motor control amount calculation means by the rotation amount calculated by the motor control amount calculation means. It is characterized in Rukoto.

  Since the rotation angle of the θ-axis motor (drive pulley) when the second driven pulley is at the origin is regular, the θ-axis motor (drive pulley) at the time when the second origin detection signal is output If the rotation angle can be detected, the current belt position (deviation amount from the origin) can be appropriately recognized based on the detected angle. Then, after recognizing the current belt position, the θ-axis motor can be rotated at once to return the belt to the origin. In this manner, the belt origin return operation can be performed appropriately and quickly.

  According to a sixth aspect of the present invention, in the electronic component mounting apparatus according to the fifth aspect of the invention, after the deviation amount calculating means detects that the first origin detecting means has output the first origin detecting signal. Each time the θ-axis motor is rotated by a predetermined angle, it is confirmed whether or not the second origin detection means outputs a second origin detection signal, and the second origin detection means The deviation amount is calculated based on the rotation angle of the θ-axis motor detected by the motor angle detection means when it is confirmed that a detection signal is output.

Thereby, even when there is a width in the range in which the second origin detection means can detect the origin of the second driven pulley (sensor reaction range), the second angle can be accurately set by appropriately setting the predetermined angle. The timing at which the origin detection signal is output can be detected.
Further, in the electromagnetic component mounting apparatus according to a seventh aspect, in the invention according to the sixth aspect, the predetermined angle is determined according to a ratio between the number of teeth of the driving pulley and the number of teeth of the second driven pulley. It is characterized by that.

  Thus, the first origin detection signal is detected after utilizing the fact that the amount of deviation from the origin of the second driven pulley when the drive pulley is at the origin, and then the second origin detection signal is detected. The θ-axis motor can be rotated so that the belt position is likely to be output. That is, since the presence or absence of the output of the second hand origin detection signal can be confirmed only at the belt position where the second origin detection signal is likely to be output, the second origin can be detected with high accuracy and efficiency. The output timing of the detection signal can be searched.

  According to the present invention, the belt is detected by the origin detection signal of the drive pulley attached to the motor shaft and the origin detection signal of the second driven pulley provided separately from the first driven pulley attached to the nozzle shaft. Since the origin of the belt can be searched, the belt can be returned to the original position without attaching a belt mark. Therefore, even if aged deterioration, belt rubbing or the like occurs, there is no influence on the belt origin return operation, and the belt origin return can be performed stably. As a result, a stable implementation can be established.

It is a top view which shows the electronic component mounting apparatus in this invention. It is a perspective view which shows the outline | summary of the mounting head and the θ-axis rotation mechanism of the mounting head. It is a top view which shows the principal part of (theta) axis | shaft rotation mechanism. It is a block diagram which shows the structure of the control system of an electronic component mounting apparatus. It is a flowchart which shows the belt origin search processing procedure of 1st Embodiment. It is a figure which shows the state of a belt, and the relationship of Z phase. It is a figure which shows the normal state of a belt, and the state developed one-dimensionally. It is a figure for demonstrating the operation | movement of 1st Embodiment. It is a figure which shows the example which provided two pulleys. It is a flowchart which shows the belt origin search processing procedure of 2nd Embodiment. It is a figure which shows the rotation angle of the pulley at the time of detecting the Z phase of an encoder. It is a flowchart which shows the belt origin search processing procedure of 3rd Embodiment. It is a figure which shows the motor encoder output at the time of detecting the Z phase of an origin sensor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
(Constitution)
FIG. 1 is a plan view showing an electronic component mounting apparatus according to the present invention.
In the figure, reference numeral 1 denotes an electronic component mounting apparatus. The electronic component mounting apparatus 1 includes a pair of transport rails 11 extending in the X direction on the upper surface of the base 10. The transport rail 11 supports both sides of the circuit board 5 and is driven by a transport motor (not shown) to transport the circuit board 5 in the X direction.

The electronic component mounting apparatus 1 includes a mounting head 12. The mounting head 12 includes a plurality of suction nozzles that suck electronic components at the bottom, and is configured to be horizontally movable on the base 10 in the XY directions by the X-axis gantry 13 and the Y-axis gantry 14.
In this electronic component mounting apparatus 1, electronic component supply devices 15 that supply electronic components by a tape feeder or the like are mounted on both sides of the transport rail 11 in the Y direction. The electronic component supplied from the electronic component supply device 15 is vacuum-sucked by the suction nozzle of the mounting head 12 and mounted on the circuit board 5.

A recognition camera 7 made up of a CCD camera is disposed between the component supply device 15 and the circuit board 5. The recognition camera 7 detects the electronic component suction position deviation (shift between the center position of the suction nozzle and the center position of the sucked component) and the suction angle shift (tilt) of the electronic component. Is taken.
A distance sensor 8 is attached to the mounting head 12. The distance sensor 8 measures the distance (height) in the Z direction between the suction nozzle and the circuit board 5 using sensor light.
Furthermore, the electronic component mounting apparatus 1 is provided with a nozzle changer 16 for exchanging the suction nozzle according to the size and shape of the component to be sucked. A plurality of types of nozzles are stored and managed in the nozzle changer 16.

FIG. 2 is a perspective view showing an outline of the mounting head 12 and the θ-axis rotation mechanism of the mounting head 12.
In the figure, reference numeral 20 denotes a θ-axis rotation mechanism. The θ-axis rotating mechanism 20 includes a θ-axis motor 21 as a drive source for rotating the suction nozzle 12b around the nozzle shaft 12a of the mounting head 12.
A driving pulley 22 is mounted on the θ-axis motor 21 on the same axis. When the θ-axis motor 21 is driven, a driven pulley (first driven pulley) 12c mounted coaxially with the nozzle shaft 12a is rotated via a belt 23 stretched around the driving pulley 22, whereby the nozzle shaft 12a is rotated. Is designed to rotate. In addition to the driving pulley 22 and the driven pulley 12c, the belt 23 is also wound around a pulley for searching the belt origin (second driven pulley) 24. When the θ-axis motor 21 is driven, the driving pulley 22 As a result, the pulley 24 also rotates via the belt 23.

Here, as shown in FIG. 3, each pulley 22, 24, and 12c is a toothed pulley, and the drive pulley 22 and the driven pulley 12c have the same number of teeth m. The belt 23 is a toothed belt, and the number of teeth L of the belt 23 matches the least common multiple of the number of teeth m of the drive pulley 22 and the number of teeth p of the pulley 24.
That is, the number of teeth L of the belt 23 is expressed by the following equation using a function LCM () that derives the least common multiple.
L = LCM (m, p) (1)

Returning to FIG. 2, the θ-axis motor 21 has a built-in encoder 25, and the motor angle of the θ-axis motor 21 can be detected from the output of the encoder 25. The encoder 25 outputs the Z phase as a first origin detection signal each time the motor shaft makes one revolution and the origin position becomes a predetermined reference position.
Further, the pulley 24 is provided with an origin sensor 26 capable of detecting the origin position of the pulley 24. The origin sensor 26 outputs a signal corresponding to the Z phase as a second origin detection signal every time the pulley 24 rotates once and the origin position becomes a predetermined reference position. It can be constituted by a type sensor.

  When the θ-axis rotating mechanism 20 is assembled, initial adjustment is performed so that both the θ-axis motor 21 and the pulley 24 are at the origin when the belt 23 is at the origin. Here, the belt 23 being at the origin means a state where the origin position α of the belt 23 is at a predetermined reference position shown in FIG. 3, and both the θ-axis motor 21 and the pulley 24 are at the origin. A state in which the origin position β of the shaft motor 21 and the origin position γ of the pulley 24 are both at the predetermined reference position shown in FIG. Each reference position can be set as appropriate.

FIG. 4 is a block diagram showing the configuration of the control system of the electronic component mounting apparatus 1.
The electronic component mounting apparatus 1 includes a controller 30 including a microcomputer including a CPU, a RAM, a ROM, and the like that control the entire apparatus. The controller 30 controls each of the components 31 to 35 shown below.
The vacuum mechanism 31 generates a vacuum and generates a negative vacuum pressure on the suction nozzle 12b via a vacuum switch (not shown).

The X-axis motor 32 is a drive source for moving the mounting head 12 in the X-axis direction along the X-axis gantry 13, and the Y-axis motor 33 is the Y-axis gantry 13 along the Y-axis gantry 14. It is a drive source for moving in the direction. When the controller 30 drives and controls the X-axis motor 32 and the Y-axis motor 33, the mounting head 12 can move in the XY directions.
The Z-axis motor 34 is a drive source for moving the suction nozzle 12b up and down in the Z direction. Although only one Z-axis motor 34 is shown here, when a plurality of suction nozzles 12b are provided, the number of suction nozzles 12b is as many as the number of suction nozzles 12b.

  The controller 30 sucks the electronic component P using the suction nozzle 12 b of the mounting head 12 and mounts the electronic component P on the circuit board 5 based on the image of the electronic component P captured by the recognition camera 7. Execute the implementation process. Further, the controller 30 performs belt origin search processing shown in FIG. 5 at a predetermined timing (for example, when the electronic component mounting apparatus 1 is turned on), searches for the origin of the belt 23, and performs origin return.

  Since the above equation (1) is established in the θ-axis rotating mechanism 20, when the belt 23 makes one round from the origin and returns to the origin, the drive pulley 22 is L / m times and the pulley 24 is L / p. Rotate each to return to the origin. The drive pulley 22 and the pulley 24 are both at the origin only when the belt 23 is at the origin. That is, when the belt 23 is deviated from the origin, the pulley 24 is deviated from the origin even if the driving pulley 22 is at the origin.

Therefore, using this configuration, in the belt origin searching process, the state where both the driving pulley 22 and the pulley 24 are at the origin is searched while the θ-axis motor 21 is rotated, and both the driving pulley 22 and the pulley 24 are at the origin. When a certain state is confirmed, the rotation of the θ-axis motor 21 is stopped at that time. In this way, the belt 23 is returned to the origin.
In the belt origin search process, as shown in FIG. 5, first, in step S1, the controller 30 rotates the θ-axis motor 21 in a certain direction (for example, the positive direction), and proceeds to step S2.

In step S2, the controller 30 determines whether or not the Z phase of the encoder 25 has been detected. If the Z phase is detected, the process proceeds to step S3. If the Z phase is not detected, the θ-axis motor 21 is rotated until it is detected, and the process proceeds to step S1.
In step S3, the controller 30 increments a counter n that counts the number of times the encoder 25 detects the Z phase after starting execution of the belt origin search process, and proceeds to step S4.

In step S4, the controller 30 confirms the state of the origin sensor 26 and determines whether or not the origin sensor 26 is in an ON state (a state in which the Z phase is output). If the origin sensor 26 is in the ON state, it is determined that both the driving pulley 22 and the pulley 24 are at the origin, and the process proceeds to step S5. If the origin sensor 26 is in the OFF state, the process will be described later. The process proceeds to step S6.
In step S5, the controller 30 stops the rotation of the θ-axis motor 21 on the assumption that the search for the belt origin has been successful, sets the current state of the belt 23 as a state where the belt 23 is at the origin, and then searches for the belt origin. The process ends.

  In step S6, the controller 30 determines whether or not the counter n has reached a predetermined value N. Here, the predetermined value N is used to determine whether or not the belt 23 has made one revolution since the start of the belt origin search process. The number of teeth L of the belt 23 and the number of teeth m of the drive pulley 22 are determined. And determined by the ratio. Specifically, using the fact that the driving pulley 22 rotates L / m when the belt 23 makes one revolution, N = L / m. If it is determined in step S6 that the counter n has not reached the predetermined value N, the process proceeds to step S1, and if it is determined that the counter n has reached the predetermined value N, the process proceeds to step S7. .

In step S7, the controller 30 performs a predetermined error process such as notifying the operator that the belt origin could not be searched even if the belt 23 makes one revolution, and ends the belt origin search process. Here, the cause of the belt origin search error may be a malfunction of the sensor unit or failure of initial adjustment.
With the above configuration, at the normal time, if the motor shaft is rotated at the maximum N (= L / m) to the origin, the origin of the belt 23 can be found and the origin can be returned.
In the above, the encoder 25 corresponds to the first origin detection means, and the origin sensor 26 corresponds to the second origin detection means. Further, steps S1 to S4 in FIG. 5 correspond to search means, and step S5 corresponds to motor stop means.

(Operation)
Next, the operation of the first embodiment will be described with reference to FIGS. Here, description will be made assuming that the number of teeth of the driving pulley 22 is m = 24, the number of teeth of the pulley 24 for searching the belt origin is p = 21, and the number of teeth of the belt 23 is L = 168.
The number of teeth m of the drive pulley 22 and the number of teeth L of the belt 23 are largely determined by the environment in which they are used. Therefore, when designing the θ-axis rotating mechanism 20, the number of teeth p satisfying the above equation (1) is derived based on the number of teeth m and the number of teeth L. When m = 24 and L = 168, the number of teeth p of the pulley 24 can be selected from among 7, 14, 21, 28, 42, 56, and 84 for calculation.
Therefore, although p = 21 is described here, other values can be arbitrarily selected from the plurality of values. Note that the number of teeth p satisfying the above equation (1) includes p = 168 in the calculation, but since it is the same as the number of teeth L of the belt 23, it cannot be actually incorporated. Therefore, p = 168 cannot be selected.

FIG. 6 is a diagram showing a relationship between the state of the belt 23 and the output timing of the Z phase, and is an image diagram in which one rotation of the belt 23 is developed in one dimension. That is, FIG. 6 is a one-dimensionally developed belt as shown in FIG. 7B, which is normally looped as shown in FIG. 7A. 7A and 7B, the inverted triangle mark (ベ ル ト) indicates the same point on the belt.
As shown in FIG. 6, when the belt 23 makes one revolution, the motor shaft rotates L / m = 7, and the encoder 25 outputs the Z phase seven times (A) to (G). Similarly, when the belt 23 makes one revolution, the pulley 24 rotates L / p = 8, and the origin sensor 26 outputs the Z phase eight times (a) to (h).

  Further, as described above, the number of teeth L of the belt 23 matches the least common multiple of the number of teeth m of the driving pulley 22 and the number of teeth p of the pulley 24, and the driving pulley 22 when the belt 23 is at the origin. And the pulley 24 are initially adjusted so that both are at the origin. Therefore, the timing at which the encoder 25 outputs the Z phase and the timing at which the origin sensor 26 outputs the Z phase match only when the belt 23 is at the origin, and do not match otherwise.

FIG. 8 is a diagram illustrating the state of the belt 23 at the time when the encoder 25 outputs the Z phase. From L / m = 168/24 = 7, there are seven possible states of the belt 23 when the encoder 25 outputs the Z-phase as shown in FIGS. 8A to 8G. 8A shows a state where the belt 23 is at the origin, and FIGS. 8B to 8G show that the belt 23 advances 1/7, 2/7,..., 6/7 around the origin. It is a state.
That is, FIGS. 8A to 8G show the state of the belt 23 when the Z phase (A) to the Z phase (G) in FIG. 6 are detected, respectively. 8A to 8G, the point α indicates the origin position of the belt 23, the point β indicates the origin position of the drive pulley 22, and the point γ indicates the origin position of the pulley 24.

When the belt origin search process shown in FIG. 5 is started, the controller 30 first rotates the θ-axis motor 21 to detect the Z phase of the encoder 25. When the Z phase detected at this time is the Z phase (B) in FIG. 6, the state of the belt 23 at that time is a state in which the belt has advanced by 1/7 round from the origin as shown in FIG. 8 (b). is there. At this time, the pulley 24 is also in a state advanced by 1/7 turn from the origin.
Thus, the amount of deviation of the belt 23 from the origin matches the amount of deviation of the pulley 24 from the origin, and when the belt 23 is at the origin, the pulley 24 is also at the origin. Therefore, when the drive pulley 22 and the pulley 24 are both at the origin, the belt 23 is at the origin. Therefore, it is confirmed whether or not the pulley 24 is also at the origin when the drive pulley 22 is at the origin.

When the driving pulley 22 detects the origin, that is, when the Z phase of the encoder 25 is detected, as shown in FIG. 8B, the pulley 24 is not at the origin, and the origin sensor 26 is in the OFF state. Therefore, the controller 30 rotates the θ-axis motor 21 until the Z phase of the encoder 25 is detected again. Then, as shown in FIG. 8C, when the belt 23 is advanced by 2/7 from the origin and the encoder 25 outputs the Z phase (C) in FIG. 6, the controller 30 at that time The state of the origin sensor 26 is confirmed. However, even in this state, the pulley 24 is advanced by 2/7 laps from the origin, and the origin sensor 26 is in the OFF state. Therefore, the controller 30 keeps the θ-axis motor 21 until the Z phase of the encoder 25 is detected again. Rotate once.
In this way, the motor shaft is rotated by one rotation to advance the belt 23 by 1/7, and the state of the origin sensor 26 is confirmed each time, and whether the pulley 24 is at the origin (the belt 23 is at the origin). Confirm).

  Then, as shown in FIG. 8 (g), when the θ-axis motor 21 is rotated once until the Z phase of the encoder 25 is detected from the state in which the belt 23 has advanced 6/7 from the origin, the state of the belt 23 is as shown in FIG. As shown in FIG. 8 (a), the state returns to the original position, and the pulley 24 also returns to the original position. Therefore, the origin sensor 26 at this time is turned on. Therefore, the controller 30 stops the rotation of the θ-axis motor 21 at this time. As a result, the belt 23 returns to the origin.

  In this embodiment, no matter what position the belt 23 is at the start of execution of the belt origin search process, if the θ-axis motor 21 is rotated to the position where the encoder 25 detects the Z phase, the belt 23 The state is always one of FIGS. 8A to 8G. Therefore, if this point is used, the belt 23 can be returned to the origin by rotating the motor shaft N times at most (seven rotations in the above example).

(effect)
As described above, in the first embodiment, the number of teeth of the belt connecting the shaft of the suction nozzle and the motor shaft is made to coincide with the least common multiple of the number of teeth of the driving pulley and the number of teeth of the pulley for searching the belt origin. With this configuration, the timing at which the drive pulley and the belt origin search pulley both coincide at the origin can be made only once while the belt makes one revolution. Then, the θ-axis rotation mechanism is assembled and the initial adjustment is made so that the drive pulley origin coincides with the belt origin search pulley origin when the belt is at the origin. By searching for the timing when the origin of the origin search pulley coincides, the origin of the belt can be searched.

  The required number of teeth on the motor shaft and the belt length vary depending on the system, but if the condition that the number of teeth on the belt is an integral multiple of the number of teeth on the motor shaft is satisfied, the number of teeth on the pulley for searching the belt origin can be determined. By adjusting, in many cases, it can be used under any conditions. Moreover, the number of teeth of the belt origin search pulley can be obtained by simple calculation, and a convenient configuration can be arbitrarily selected.

  Further, when searching for the belt origin, the Z-phase output from the encoder of the θ-axis motor is detected, and the θ-axis motor is rotated in a fixed direction by one rotation on the basis of the time point when the Z-phase is detected. The state of the origin sensor for detecting the origin of the pulley for searching the belt origin every time is rotated is confirmed. When it is confirmed from the origin sensor state that the belt origin search pulley is at the origin, the rotation of the θ-axis motor is stopped at that time. As a result, the belt origin can be reliably restored.

That is, the belt origin return can be performed without attaching a belt mark as in the conventional method. Therefore, even if aged deterioration, belt rubbing, or the like occurs, the belt origin search accuracy is not affected, and the belt origin return can be performed stably. As a result, a stable implementation can be established.
Further, the origin sensor for detecting the origin of the pulley for searching the belt origin can be applied to any configuration as long as the origin (Z-phase) of one round of the pulley can be known. Therefore, since it is not necessary to know the detailed angle of the pulley, an inexpensive sensor can be used.

(Modification)
In the first embodiment, the case where only one pulley for searching the belt origin is provided has been described, but a plurality of pulleys may be provided. For example, when the number of teeth L of the belt 23 is 144 and the number of teeth m of the drive pulley 22 is 24, the number of teeth p satisfying the above expression (1) does not exist other than 144 equal to the number of teeth L of the belt 23. . A pulley for searching the belt origin with the number of teeth p = 144 cannot be incorporated into the θ-axis rotation mechanism 20 with the number of teeth L = 144. In such a case, a plurality of pulleys for searching the belt origin should be provided. Realize with.
That is, as expressed by the following equation, the least common multiple of the number of teeth m of the driving pulley 22 and the number of teeth p1,... It is made equal to the number L.
L = LCM (m, p1,..., Pk) (2)

For example, in the case of the above example (L = 144, m = 24), as shown in FIG. 9, two pulleys for belt origin search are provided, and the number of teeth (p1, p2) of these two pulleys is ( 16, 18). In the example shown in FIG. 9, (p1, p2) = (16, 18), but (p1, p2) satisfying the above equation (2) is calculated from (9, 16), (9, 48), (16, 18), (16, 36), (18, 48), (16, 72), (36, 48), (48, 72) exist. Therefore, (p1, p2) can be arbitrarily selected from the above.
When a plurality of pulleys for searching the belt origin are provided, an origin sensor is provided for each pulley. In step S4 of the belt origin search process shown in FIG. 5, it is determined whether all the origin sensors are in the ON state. Make a decision. With such a configuration, it is possible to obtain the same effect as when only one pulley for searching the belt origin is provided.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.
In the second embodiment, an angle sensor (pulley angle detecting means) capable of detecting the rotation angle of the pulley 24 is provided in place of the origin sensor 26 in the first embodiment described above.

(Constitution)
The θ-axis rotation mechanism 20 in this embodiment includes an angle sensor that can detect the rotation angle of the pulley 24 instead of the origin sensor 26 in FIG. 2. Then, in the belt origin search process, the controller 30 detects the amount of deviation from the origin of the belt 23 at that time based on the rotation angle of the pulley 24 at the time when the Z phase of the encoder 25 is detected. The origin of the belt 23 is returned by rotating the θ-axis motor 21 so that the amount becomes zero.
FIG. 10 is a flowchart illustrating a belt origin search processing procedure in the second embodiment.
First, in step S11, the controller 30 rotates the θ-axis motor 21 in a certain direction (for example, the positive direction), and proceeds to step S12.

In step S12, the controller 30 determines whether or not the Z phase of the encoder 25 has been detected. If the Z phase is detected, the process proceeds to step S13. If the Z phase is not detected, the θ-axis motor 21 is rotated until it is detected, and the process proceeds to step S11.
In step S13, the controller 30 acquires the rotation angle of the pulley 24 detected by the angle sensor, and proceeds to step S14.
In step S14, the controller 30 determines whether or not the origin of the belt 23 can be searched based on the rotation angle of the pulley 24 acquired in step S13.

  When the above-described initial adjustment is performed, there is a certain law for the rotation angle of the pulley 24 at the time when the Z phase of the encoder 25 is detected, and the angles are the number of teeth m of the driving pulley 22 and the number of teeth of the pulley 24. It depends on the ratio to p. If the rotation angle of the pulley 24 at the time when the Z phase of the encoder 25 is detected is known, it can be determined how much the belt 23 is deviated from the origin. This point will be specifically described with reference to FIG. FIG. 11 is an image diagram in which one rotation of the belt 23 is developed in a one-dimensional manner. That is, as shown in FIG. 7 (a), a belt which is normally in a loop shape is shown in a one-dimensional development as shown in FIG. 7 (b).

  In the example shown in FIG. 11, the number of teeth of the driving pulley 22 is m = 24, the number of teeth of the pulley 24 is p = 21, and the number of teeth of the belt 23 is L = 168. The rotation angle of the pulley 24 when the encoder 25 detects the Z phase is 0 ° when the Z phase (A) is detected (belt origin). Then, 360 ° / 7≈51 ° when detecting the Z phase (B), 360 ° / 7 × 2≈103 ° when detecting the Z phase (C), and 360 ° / 7 × 3 when detecting the Z phase (D). ≒ 154 °, 360 ° / 7 × 4 ≒ 206 ° when Z phase (E) is detected, 360 ° / 7 × 5 ≒ 257 ° when Z phase (F) is detected, 360 ° when Z phase (G) is detected / 7 × 6≈309 °.

  Therefore, when the rotation angle of the pulley 24 detected by the angle sensor when the encoder 25 detects the Z phase is 51 °, for example, the detected Z phase is the Z phase (B) in FIG. Therefore, in this case, since it can be seen that the belt 23 is displaced by 1/7 of the turn in the forward direction, it can be seen that the belt 23 can be returned to the origin by rotating the motor shaft one turn in the reverse direction.

  Therefore, in step S14, the rotation angle of the pulley 24 acquired in step S13 is determined according to the ratio between the number of teeth m of the driving pulley 22 and the number of teeth p of the pulley 24. It is determined whether or not. For example, in the example of FIG. 11, when the rotation angle of the pulley 24 is an angle that provides an allowable range (± several degrees) to j times 360 ° / 7 (j is an integer of 1 to 7), the belt 23 It is determined that the origin is an angle that can be searched. And when it determines with the origin of the belt 23 being searchable, it transfers to step S15.

In step S15, the controller 30 obtains the amount of deviation from the origin of the belt 23 from the rotation angle of the pulley 24 acquired in step S13, and the θ-axis motor 21 necessary for returning the belt 23 to the origin by the shortest path. Calculate the direction and amount of rotation.
For example, in the example shown in FIG. 11, when the rotation angle of the pulley 24 is 0 °, the belt 23 is at the origin, so the θ-axis motor 21 does not need to rotate and the rotation amount is set to 0. On the other hand, when the rotation angle of the pulley 24 is 51 °, it is in the Z phase (B) detection state. Therefore, in order to return the belt 23 to the origin by the shortest path, it is necessary to rotate the θ-axis motor 21 once in the reverse direction. Suppose that the rotation direction is the reverse direction and the rotation amount is 360 °. Similarly, when the rotation angle of the pulley 24 is 103 °, the θ-axis motor 21 needs to be rotated twice in the reverse direction, and the rotation direction is the reverse direction and the rotation amount is 720 °. Furthermore, when the rotation angle of the pulley 24 is 154 °, the θ-axis motor 21 needs to be rotated three times in the reverse direction, and the rotation direction is the reverse direction and the rotation amount is 1080 °.

  Further, when the rotation angle of the pulley 24 is 154 °, it is necessary to rotate the θ-axis motor 21 three times in the forward direction in order to return the belt 23 to the origin through the shortest path. The rotation amount is set to 1080 °. When the rotation angle of the pulley 24 is 206 °, the θ-axis motor 21 needs to be rotated twice in the forward direction, and the rotation direction is the forward direction and the rotation amount is 720 °. Similarly, when the rotation angle of the pulley 24 is 309 °, the θ-axis motor 21 needs to be rotated once in the forward direction, and the rotation direction is the forward direction and the rotation amount is 360 °.

  Here, the rotation angle of the pulley 24 is determined in consideration of the allowable range. That is, for example, when the detected value detected by the angle sensor is 0 ° ± allowable range, the rotation angle of the pulley 24 is 0 °, and when the detected value detected by the angle sensor is 51 ° ± allowable range, The rotation direction and amount of rotation of the θ-axis motor 21 are calculated assuming that the rotation angle of the pulley 24 is 51 °.

Next, in Step S16, the controller 30 rotates the θ-axis motor 21 in the rotation direction obtained in Step S15 by the rotation amount obtained in Step S15, and proceeds to Step S17.
In step S <b> 17, the controller 30 finishes the belt origin search process on the assumption that the origin return of the belt 23 has been completed when the rotation of the θ-axis motor 21 is completed.

If it is determined in step S14 that the belt origin cannot be searched, the process proceeds to step S18, and the controller 30 notifies the operator that the belt origin cannot be searched. Predetermined error processing is performed, and the belt origin search processing is terminated. Here, the cause of the belt origin search error may be a malfunction of the sensor unit or failure of initial adjustment.
Note that steps S11 to S14 in FIG. 10 correspond to the deviation amount calculating means, step S15 corresponds to the motor control amount calculating means, and step S16 corresponds to the motor driving means.

(Operation)
Next, the operation of the second embodiment will be described. Here, as shown in FIG. 11, description will be made using an example in which the number of teeth of the driving pulley 22 is m = 24, the number of teeth of the pulley 24 for searching the belt origin p = 21, and the number of teeth of the belt 23 is L = 168.
When the belt origin search process shown in FIG. 10 is started, the controller 30 first rotates the θ-axis motor 21 to detect the Z phase of the encoder 25. Then, the rotation angle of the pulley 24 at that time is detected by an angle sensor.
At this time, if the angle sensor detects that the rotation angle of the pulley 24 is 51 °, since the angle is an angle at which the belt origin can be searched, the controller 30 determines the belt based on the detected angle. The rotation direction and amount of rotation of the θ-axis motor 21 necessary for returning the position 23 to the origin are calculated.

  Since the rotation angle of the pulley 24 is 51 °, the controller 30 determines that the state of the belt 23 at the time when the Z phase of the encoder 25 is detected is a state in which the forward direction advances by 1/7. Therefore, it is determined that if the motor shaft is rotated once in the reverse direction, the belt 23 can be returned to 1/7 of the reverse direction, and the belt 23 can be returned to the origin by the shortest path. Therefore, the controller 30 sets the rotation direction in the reverse direction, sets the rotation amount to 360 ° for one round, and rotates the θ-axis motor 21 in the reverse direction by 360 °. As a result, the belt 23 returns to the origin.

As described above, by detecting the rotation angle of the pulley 24 at the time when the Z phase of the encoder 25 is detected, the deviation amount from the origin of the belt 23 is grasped, and then the θ-axis motor 21 is rotated. Rotates the amount of rotation necessary for return to origin at once. Therefore, after detecting the Z phase of the encoder 25, the origin can be quickly returned without rotating the θ-axis motor 21 many times.
In this embodiment, the case where only one pulley for searching the belt origin is provided has been described. However, the present invention can also be applied to a case where a plurality of pulleys are provided as shown in FIG.

(effect)
As described above, in the second embodiment, since the angle sensor for detecting the current angle of the pulley for searching the belt origin is provided, the angle of the pulley at the time when the Z phase of the motor encoder is detected is determined at that time. The state of the belt (the amount of deviation from the origin) can be recognized. Therefore, after detecting the Z phase of the motor encoder, the belt can be returned to the origin at a stroke. Therefore, the belt can be returned to the original position without repeating N times (L / m times) as in the first embodiment. As a result, the time required for the return to origin can be shortened.
In addition, after detecting the Z phase of the motor encoder, the rotation direction and the rotation amount of the θ-axis motor are calculated so that the origin is returned by the shortest path, so that the origin can be returned more quickly.

(Third embodiment)
Next, a third embodiment of the present invention will be described.
In the third embodiment, the current position of the belt 23 is grasped based on the rotation angle of the pulley 24 when the Z phase of the encoder 25 is detected in the second embodiment described above. On the other hand, the current position of the belt 23 is grasped based on the rotation angle of the θ-axis motor 21 when the Z-phase of the origin sensor 26 installed on the pulley 24 is detected.

(Constitution)
The θ-axis rotation mechanism 20 in the present embodiment has the same configuration as the θ-axis rotation mechanism 20 shown in FIG. Then, the controller 30 obtains the rotation angle of the θ-axis motor 21 at the time when the Z phase of the origin sensor 26 is detected in the belt origin search process, and based on the obtained angle, from the origin of the belt 23 at that time. The amount of deviation is detected.
FIG. 12 is a flowchart illustrating a belt origin search processing procedure in the third embodiment.

First, in step S21, the controller 30 rotates the θ-axis motor 21 in a certain direction (for example, the positive direction), and proceeds to step S22.
In step S22, the controller 30 determines whether or not the Z phase of the encoder 25 has been detected. If the Z phase is detected, the process proceeds to step S23. If the Z phase is not detected, the θ-axis motor 21 is rotated until it is detected, and the process proceeds to step S21.
In step S23, the controller 30 confirms the state of the origin sensor 26 and determines whether or not the origin sensor 26 is in an ON state. When the origin sensor 26 is in the OFF state, the process proceeds to step S24, and when the origin sensor 26 is in the ON state, the process proceeds to step S27 described later.

In step S24, the controller 30 determines whether or not the search for the belt origin has failed. Here, after detecting the Z phase of the encoder 25, it is determined whether or not the θ-axis motor 21 has been rotated by an angle that theoretically detects the Z phase of the origin sensor 26. For example, when the number of teeth m of the driving pulley 22 is larger than the number of teeth p of the pulley 24, the Z phase of the origin sensor 26 can be detected at least once while the θ-axis motor 21 is rotated 360 °. Therefore, in such a case, after detecting the Z phase of the encoder 25, it is determined whether or not the θ-axis motor 21 has been rotated 360 °. Judge that
If it is determined in step S24 that the search for the belt origin has failed, the process proceeds to step S25, and a predetermined error process such as notifying the operator that the search for the belt origin has failed is performed. The origin search process ends. Here, the cause of the belt origin search error may be a malfunction of the sensor unit or failure of initial adjustment.

On the other hand, if it is not determined in step S24 that the search for the belt origin has failed, the process proceeds to step S26, and the controller 30 rotates the θ-axis motor 21 in the forward direction by a predetermined angle θ ₀ ° and proceeds to step S23. Transition. Here, the predetermined angle θ ₀ is determined based on the ratio between the number of teeth m of the driving pulley 22 and the number of teeth p of the pulley 24.
FIG. 13 is a diagram showing a motor encoder output at the time when the origin sensor 26 detects the Z phase. FIG. 13 is an image diagram in which one rotation of the belt 23 is developed in one dimension. That is, as shown in FIG. 7 (a), a belt which is normally in a loop shape is shown in a one-dimensional development as shown in FIG. 7 (b).

  In the example shown in FIG. 13, the number of teeth of the drive pulley 22 is m = 24, the number of teeth of the pulley 24 is p = 21, and the number of teeth of the belt 23 is L = 168. When the above-described initial adjustment is performed, the motor encoder output is 0 ° when the origin sensor 26 detects the Z phase (a) (belt origin). 315 ° when detecting the Z phase (b), 270 ° when detecting the Z phase (c), 225 ° when detecting the Z phase (d), 180 ° when detecting the Z phase (e), and Z phase (f ) Is detected at 135 °, Z phase (g) is detected at 90 °, and Z phase (h) is detected at 45 °. Thus, when the ratio of the number of teeth m to the number of teeth p is 8: 7, the motor encoder output at the time when the Z phase of the origin sensor 26 is detected is a multiple of 45 °.

Therefore, in the example shown in FIG. 13, if the θ-axis motor 21 is rotated forward by 45 ° on the basis of the time point when the Z phase of the encoder 25 is detected, before the Z phase of the encoder 25 is detected again. It always coincides with the timing of detecting the Z phase of the origin sensor 26 somewhere. Therefore, in this case, a predetermined angle θ ₀ = 45 ° is set, and it is checked whether or not the origin sensor 26 reacts (turns on) every time the θ-axis motor 21 is rotated 45 ° in the forward direction. This operation is repeated until the origin sensor 26 reacts, and if the motor encoder output when the origin sensor 26 reacts is acquired, the deviation amount from the origin of the belt 23 at that time can be grasped from the motor encoder output. it can.

In step S27, the controller 30 acquires the motor angle from the output of the encoder 25, and proceeds to step S28.
In step S28, the controller 30 obtains the amount of deviation from the origin of the belt 23 from the motor angle acquired in step S27, and the rotational direction of the θ-axis motor 21 required to return the belt 23 to the origin along the shortest path and Calculate the amount of rotation.

  For example, in the example shown in FIG. 13, when the motor angle is 0 °, the belt 23 is at the origin, so the θ-axis motor 21 does not need to rotate and the rotation amount is set to 0. Further, when the motor angle is 315 °, it is in the Z-phase (b) detection state, and therefore the θ-axis motor 21 needs to be rotated 315 ° in the reverse direction in order to return the belt 23 to the origin through the shortest path. The rotation direction is the reverse direction, and the rotation amount is 315 °. Similarly, when the motor angle is 270 °, the θ-axis motor 21 needs to be rotated 360 ° + 270 ° in the reverse direction, and the rotation direction is the reverse direction and the rotation amount is 630 °. Furthermore, when the motor angle is 225 °, the θ-axis motor 21 needs to be rotated 720 ° + 225 ° in the reverse direction, and the rotation direction is the reverse direction and the rotation amount is 945 °.

  When the motor angle is 180 °, it is in the Z phase (e) detection state. Therefore, in order to return the belt 23 to the origin, it is necessary to rotate the θ-axis motor 21 by 1080 ° + 180 ° in the forward direction. Assuming that the rotation direction is the forward direction, the rotation amount is 1260 °. When the motor angle is 180 °, the rotation direction may be the reverse direction and the rotation amount may be 1260 °.

  Further, when the motor angle is 135 °, it is in the Z phase (f) detection state. Therefore, in order to return the belt 23 to the origin by the shortest path, the θ-axis motor 21 is moved forward by 720 ° + (360 (° −135 °), the rotation direction is assumed to be the forward direction and the rotation amount is assumed to be 945 °. Similarly, when the motor angle is 90 °, it is necessary to rotate the θ-axis motor 21 in the forward direction by 360 ° + (360 ° −90 °). 630 °. When the motor angle is 45 °, it is necessary to rotate the θ-axis motor 21 in the forward direction (360 ° -45 °), and the rotation direction is the forward direction and the rotation amount is 315 °. .

  Here, the determination of the motor angle is performed in consideration of a predetermined allowable range (± several degrees). That is, for example, when the detection value detected by the encoder 25 is 315 ° ± allowable range, the motor angle is 315 °, and when the detection value detected by the encoder 25 is 270 ° ± allowable range, the motor angle is The rotation direction and amount of rotation of the θ-axis motor 21 are calculated assuming that the angle is 270 °.

Next, in Step S29, the controller 30 rotates the θ-axis motor 21 in the rotation direction obtained in Step S28 by the rotation amount obtained in Step S28, and proceeds to Step S30.
In step S30, when the rotation of the θ-axis motor 21 is finished, the controller 30 finishes the belt origin search process assuming that the origin return of the belt 23 is completed.
In the above, the encoder 25 corresponds to the motor angle detection means. Also, steps S21 to S27 in FIG. 2 correspond to the deviation amount calculating means, step S28 corresponds to the motor control amount calculating means, and step S29 corresponds to the motor driving means.

(Operation)
Next, the operation of the third embodiment will be described. Here, as shown in FIG. 13, description will be made using an example in which the number of teeth of the driving pulley 22 is m = 24, the number of teeth of the pulley 24 for searching the belt origin p = 21, and the number of teeth of the belt 23 is L = 168.
When the belt origin search process shown in FIG. 12 is started, the controller 30 first rotates the θ-axis motor 21 to detect the Z phase of the encoder 25. Then, from this point, the θ-axis motor 21 is rotated in the forward direction by a predetermined angle θ ₀ , and it is confirmed whether or not the origin sensor 26 reacts each time.

For example, in the example shown in FIG. 13, when the Z axis of the encoder 25 is detected by rotating the θ-axis motor 21 from a state where the belt 23 has slightly advanced from the origin, the belt 23 at that time is 1 / It is in a state advanced 7 laps. When the θ-axis motor 21 is rotated in the forward direction by a predetermined angle θ ₀ = 45 ° from this state, the Z-phase (c) of the origin sensor 26 is detected when the θ-axis motor 21 is rotated six times. That is, the motor encoder output at this time is 45 ° × 6 = 270 °.

When it is detected that the rotation angle of the θ-axis motor 21 is 270 ° when the origin sensor 26 detects the Z phase (c), the controller 30 moves the belt 23 to the origin based on the detected angle. The rotational direction and amount of rotation of the θ-axis motor 21 necessary for returning to the initial value are calculated.
Since the rotation angle of the θ-axis motor 21 is 270 °, the controller 30 can return the belt 23 to the origin by the shortest path if the θ-axis motor 21 is rotated 360 ° + 270 ° = 630 ° in the reverse direction. Judge that you can. Accordingly, the controller 30 sets the rotation direction in the reverse direction, sets the rotation amount to 630 °, and rotates the θ-axis motor 21 in the reverse direction by 630 °. As a result, the belt 23 returns to the origin.

As described above, the θ-axis motor 21 is rotated by a predetermined angle θ ₀ from the time when the Z phase of the encoder 25 is detected, the reaction of the origin sensor 26 is confirmed, and the θ when the Z phase of the origin sensor 26 is detected is detected. By detecting the rotation angle of the shaft motor 21, the amount of deviation from the origin of the belt 23 is grasped. Further, when the origin sensor 26 detects the Z phase, the θ-axis motor 21 is determined according to the ratio of the number of teeth m of the driving pulley 22 and the number of teeth p of the pulley 24 from the time when the Z phase of the encoder 25 is detected. Rotate by angle θ ₀ .

  Thereby, it is possible to confirm whether or not the origin sensor 26 actually reacts at the belt position where the origin sensor 26 may react. Therefore, even when the origin sensor 26 has a predetermined width in the reaction angle (origin detectable range) and the origin sensor 26 reacts even if the pulley 24 is slightly deviated from the origin, the pulley 26 is accurately located at the origin. Can be detected.

Then, after detecting the Z phase of the origin sensor 26, the θ-axis motor 21 is rotated at a stroke by the amount of rotation necessary for the origin return. Therefore, after detecting the Z phase of the origin sensor 26, it is possible to quickly return to the origin without rotating the θ-axis motor 21 many times.
In this embodiment, the case where only one pulley for searching the belt origin is provided has been described. However, the present invention can also be applied to a case where a plurality of pulleys are provided as shown in FIG.
Further, when the origin sensor 26 is configured to detect only a pinpoint without having a width in the reaction angle (detectable range), the Z of the origin sensor 26 is based on the time point when the Z phase of the encoder 25 is detected. Instead of detecting the phase, the Z phase of the origin sensor 26 may be detected while directly rotating the θ-axis motor 21 immediately after the start of the belt origin search process.

(effect)
As described above, in the third embodiment, the current belt position can be grasped based on the rotation angle of the θ-axis motor at the time when the origin of the belt origin search pulley is detected. The pulley for searching for the origin only needs to be provided with an inexpensive origin sensor, and there is no need to provide an expensive angle sensor capable of detecting the rotation angle of the pulley.

Further, when detecting the origin of the belt origin search pulley, a method is used in which the θ-axis motor is rotated by a predetermined angle from the time when the Z phase of the motor encoder is detected, and the response of the origin sensor is confirmed. At this time, the predetermined angle is set according to the ratio between the number of teeth of the driving pulley and the number of teeth of the pulley for searching the belt origin. As a result, it is possible to confirm whether or not the origin sensor actually reacts only at the belt position where the origin sensor may react. Therefore, the reaction angle (origin detection range) of the origin sensor can be confirmed. The origin of the pulley for searching the belt origin can be detected with high accuracy.
After grasping the current belt position based on the rotation angle of the θ-axis motor at the time of detecting the origin of the belt origin search pulley, the belt can be returned to the origin at once. The time required for return can be shortened.

(Application examples)
In the second and third embodiments, when the belt 23 is at the origin, the case where the assembly operation is performed by performing the initial adjustment so that the drive pulley 22 and the pulley 24 are both at the origin has been described. However, this can be realized without performing the initial adjustment.
The Z phase of the θ-axis motor 21 cannot be accurately detected unless the power is turned on to operate. Further, when the θ-axis rotating mechanism 20 such as the belt 23 is assembled, it is difficult to turn on the power to the θ-axis motor 21, and even if it can be done, the man-hour increases. Therefore, the number of steps can be reduced by performing the assembly work without performing the initial adjustment. At that time, the operation must be performed in consideration of the fact that an offset (deviation) is added to the origin position of the drive pulley 22, but operation is sufficient if the value taking into account the offset value is set for each detected angle. Is possible.

For example, in the case of the second embodiment described above, the belt origin search process is performed on the assumption that the rotation angle of the pulley 24 detected by the angle sensor includes an offset value (fixed value). For example, in the example shown in FIG. 11, the allowable range used for determination of the detection value of the angle sensor is ± 25 °.
Specifically, when the detected value of the angle sensor is 0 ° ± 25 ° (335 ° to 25 °), it is determined that the rotation angle of the pulley 24 is 0 ° and the belt 23 is at the origin. To do. Further, when the detected value of the angle sensor is 51 ° ± 25 ° (26 ° to 76 °), the rotation angle of the pulley 24 is 51 °, and the belt 23 has advanced 1/7 round from the origin. It is determined that the state is the Z phase (B) detection state.

  Similarly, when the detected value of the angle sensor is 103 ° ± 25 ° (78 ° to 128 °), the rotation angle of the pulley 24 is 103 °, and the detected value of the angle sensor is 154 ° ± 25 ° (129 ° to 179 °). ), The rotation angle of the pulley 24 is 154 °, and when the detection value of the angle sensor is 206 ° ± 25 ° (181 ° to 231 °), the rotation angle of the pulley 24 is 206 ° and the detection value of the angle sensor is 257. When the angle is ± 25 ° (232 ° to 282 °), the rotation angle of the pulley 24 is 257 °. When the detected value of the angle sensor is 309 ° ± 25 ° (284 ° to 334 °), the rotation angle of the pulley 24 is Suppose that it is 309 degrees.

Here, the allowable range “± 25 °” is determined based on the ratio between the number of teeth m of the driving pulley 22 and the number of teeth p of the pulley 24, and in the above example, m: p = 7: 8. The value matches or substantially matches half of 51 °.
Further, at this time, the offset value of the drive pulley 22 can be detected from the deviation amount from the theoretical value of the detected value of the angle sensor (0 °, 51 °, 103 °, etc. in the example of FIG. 11). Therefore, the offset value once detected is stored and used as an offset value (reference value) for the next time and thereafter. Thereby, the belt origin search process can be more appropriately performed.

In the case of the third embodiment described above, the belt origin search process is performed assuming that the encoder value (angle) of the θ-axis motor 21 includes an offset value (fixed value). That is, in the example shown in FIG. 13, the allowable range used for determining the motor angle is ± 22 °.
Specifically, when the motor encoder output is 0 ° ± 22 °, the motor encoder output is 0 °, and it is determined that the belt 23 is at the origin. When the motor encoder output is 315 ° ± 22 °, the motor encoder output is 315 °, and the belt 23 is advanced by 1/8 turn from the origin (detection state of the Z phase (b)). It is judged that.

  Similarly, when the motor encoder output is 270 ° ± 22 °, the motor encoder output is 270 °, and when the motor encoder output is 225 ° ± 22 °, the motor encoder output is 225 ° and the motor encoder output is 180 ° ± 22 °. If the motor encoder output is 180 °, the motor encoder output is 135 ° ± 22 °, the motor encoder output is 135 °, the motor encoder output is 90 ° ± 22 °, the motor encoder output is 90 °, the motor encoder When the output is 45 ° ± 22 °, the motor encoder output is 45 °.

Here, the allowable range “± 22 °” is determined based on the ratio between the number of teeth m of the driving pulley 22 and the number of teeth p of the pulley 24, and in the above example, m: p = 7: 8. The value coincides with or substantially coincides with half of 45 °. In this case, if the angle at which the θ-axis motor 21 is rotated (predetermined angle θ ₀ ) is set to a relatively small value of about 5 ° in step S26 of FIG. 12, the origin sensor 26 can surely obtain a reaction.

Note that the predetermined angle θ ₀ in this case can also be set according to the reaction angle (detectable range) of the origin sensor 26. In general, the origin control sensor is more difficult to detect and control if it detects only pinpoints without having a width in the detectable range. To make installation and control easier, the origin sensor should have a certain width. ing. Therefore, when this width is larger than the reference value θ _TH (in the example shown in FIG. 13, 45 ° because m: p = 7: 8) (however, smaller than θ _TH × 2), the predetermined angle θ Set ₀ = θ _TH . On the other hand, if: theta _TH sets a predetermined angle theta ₀ to less than half of the detectable range of the width of the origin sensor 26 (angle). In the example shown in FIG. 13, since it does not deviate by 45 ° or more (even if it is deviated, it does not deviate because it corresponds to the Z phase of the next θ-axis motor 21). It becomes possible.

  DESCRIPTION OF SYMBOLS 1 ... Electronic component mounting apparatus, 5 ... Circuit board, 11 ... Conveying rail, 12 ... Mounting head, 12a ... Nozzle shaft, 12b ... Adsorption nozzle, 12c ... Driven pulley (1st driven pulley), 13 ... X-axis gantry, DESCRIPTION OF SYMBOLS 14 ... Y-axis gantry, 15 ... Parts supply apparatus, 16 ... Nozzle changer, 20 ... (theta) axis rotation mechanism, 21 ... (theta) axis motor, 22 ... Drive pulley, 23 ... Belt, 24 ... Belt origin search pulley (2nd Driven pulley), 25 ... encoder, 26 ... origin sensor, 30 ... controller, 31 ... vacuum mechanism, 32 ... X-axis motor, 33 ... Y-axis motor, 34 ... Z-axis motor

Claims (7)

An electronic component mounting apparatus that sucks an electronic component by a suction nozzle mounted on a nozzle shaft rotated by a θ-axis motor and mounts the electronic component on a substrate,
A toothed drive pulley mounted coaxially with the shaft of the θ-axis motor;
A toothed first driven pulley mounted on the nozzle shaft coaxially with the nozzle shaft;
A second driven pulley with at least one tooth;
Teeth having a number of teeth spanning the drive pulley, the first driven pulley, and the second driven pulley and having a number equal to the least common multiple of the number of teeth of the drive pulley and the number of teeth of the second driven pulley With the belt
First origin detection means for outputting a first origin detection signal when the drive pulley is at the origin;
Second origin detection means for outputting a second origin detection signal when the second driven pulley is at the origin;
Origin return for returning the belt to the origin based on the first origin detection signal output by the first origin detection means and the second origin detection signal output by the second origin detection means. And an electronic component mounting apparatus.   2. The electronic component mounting apparatus according to claim 1, wherein when the belt is at an origin, the drive pulley and the second driven pulley are both assembled at the origin. The origin return means includes
Search means for searching the timing at which the first origin detection means and the second origin detection means simultaneously output origin detection signals while rotating the θ-axis motor;
The electronic component mounting apparatus according to claim 2, further comprising: a motor stop unit that stops the rotation of the θ-axis motor at a timing searched by the search unit. A pulley angle detecting means for detecting a rotation angle of the second driven pulley;
The origin return means includes
Based on the rotation angle of the second driven pulley detected by the angle detection means when the first origin detection means outputs the first origin detection signal, the deviation of the belt from the origin at that time A deviation amount calculating means for calculating the amount;
Motor control amount calculation means for calculating the rotation direction and the rotation amount of the θ-axis motor necessary for returning the belt to the origin based on the deviation amount from the origin of the belt calculated by the deviation amount calculation means; ,
3. A motor drive unit that rotates the θ-axis motor in a rotation direction calculated by the motor control amount calculation unit by a rotation amount calculated by the motor control amount calculation unit. The electronic component mounting apparatus described in 1. Motor angle detecting means for detecting the rotation angle of the θ-axis motor;
The origin return means includes
Based on the rotation angle of the θ-axis motor detected by the motor angle detection means when the second origin detection means outputs a second origin detection signal, the amount of deviation from the origin of the belt at that time Deviation amount calculating means for calculating
Motor control amount calculation means for calculating the rotation direction and the rotation amount of the θ-axis motor necessary for returning the belt to the origin based on the deviation amount from the origin of the belt calculated by the deviation amount calculation means; ,
3. A motor drive unit that rotates the θ-axis motor in a rotation direction calculated by the motor control amount calculation unit by a rotation amount calculated by the motor control amount calculation unit. The electronic component mounting apparatus described in 1. The deviation amount calculating means includes:
After detecting that the first origin detection means has output the first origin detection signal, the second origin detection means causes the second origin detection signal to be output every time the θ-axis motor is rotated by a predetermined angle. Based on the rotation angle of the θ-axis motor detected by the motor angle detection means when it is confirmed that the second origin detection means has output a second origin detection signal. The electronic component mounting apparatus according to claim 5, wherein the shift amount is calculated.   The electronic component mounting apparatus according to claim 6, wherein the predetermined angle is determined according to a ratio between the number of teeth of the driving pulley and the number of teeth of the second driven pulley.

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